Pesky CC number

[Boomerbull]

About 9 days ago my CC spiked to 1.5ppm so I decided to SLAM the pool to get that number down.

My CYA is 40ppm, so I would add enough liquid bleach to get the FC to 20ppm at night, and it would drop to about 16ppm the next night when I would add more to get it back to 20ppm. Rinse/repeat for about 3 nights and then my CC hit 0.5ppm (slight pink after developer is added, but disappears after 1 drop). So I decided to give it another night to try for 0.0. Next night 0.5ppm again (same thing). After 4 nights of that I decided to give it the overnight FC loss test. It lost 0.5ppm FC so I decided I was done SLAMing.

After two days of adding no chlorine my FC hit 8ppm today for a nice swimmable level…. But CC is back to 1.5ppm!

No visible algae…… what gives? Should I keep SLAMing?

 

[mknauss]

Be sure to clean the test vial you use for FC testing with alcohol or bleach.

 

[Boomerbull]

So I JUST cleaned the vial with 70% isopropyl last night. Numbers stayed the same

 

[mknauss]

With your tiny pool volume, I would not be messing with all this trouble. Dump and start over.

CC is created by ammonia based contaminants being oxidized by chlorine. Those contaminants are typically human or animal waste (urine and/or fecal).

 

[Boomerbull]

So you think I have something I can’t kill with superchlorination?

 

[Bperry]

So you think I have something I can’t kill with superchlorination?

No, just the chlorine needed may be more expensive than replacing the water.

 

[JamesW]

About 9 days ago my CC spiked to 1.5ppm so I decided to SLAM the pool to get that number down.

CC does not just spike for no reason.

Did you get heavy use?

Did you use any MPS, sulfamic acid (Copper stain remover) or anything unusual?

 

[JamesW]

If you are passing an OCLT, then I would doubt the CC reading.

Do you smell chloramines?

Did the CYA suddenly drop for no reason?

 

[Boomerbull]

So my dark secret is that my 1185 gallon “spa” is just an intex metal frame pool. The stupid drain has a small drip of a leak requiring me to fill about 10% every couple days. Which means I naturally lose CYA so I can’t be certain if I’m losing it faster than I should. My gut feeling is that I lost more CYA in the last 2 weeks then I should have.

What is that an indicator of if I’m losing CYA?

I don’t really smell chloramines, but I’m also not very sensitive to it.

 

[Bperry]

What is that an indicator of if I’m losing CYA?

Ammonia contamination. But your CYA would be gone. Either way, the fix for that is to keep adding chlorine to break down the ammonia.

Or just replace all the water. Would be a good time to fix your leak as well. Long term water leaks lead to algae on the ground, insects, other stuff that’s not good.